Multi-Functional Ingester System For Additive Manufacturing

ABSTRACT

A method and an apparatus for collecting powder samples in real-time in powder bed fusion additive manufacturing may involves an ingester system for in-process collection and characterizations of powder samples. The collection may be performed periodically and uses the results of characterizations for adjustments in the powder bed fusion process. The ingester system of the present disclosure is capable of packaging powder samples collected in real-time into storage containers serving a multitude purposes of audit, process adjustments or actions.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 16/778,860, filed on Jan. 31, 2020, which is a continuation ofU.S. patent application Ser. No. 15/336,239, filed on Oct. 27, 2016,which claims priority benefit of:

U.S. Patent Application No. 62/248,758, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,765, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,770, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,776, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,783, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,791, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,799, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,966, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,968, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,969, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,980, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,989, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,780, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,787, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,795, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,821, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,829, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,833, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,835, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,839, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,841, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,847, filed on Oct. 30, 2015, and

U.S. Patent Application No. 62/248,848, filed on Oct. 30, 2015. All ofthe foregoing are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure generally relates to three-dimensional (3D)powder bed fusion additive manufacturing and, more particularly, toin-process (in real-time or in-situ) collection and sampling of powderedmaterials during a print cycle.

BACKGROUND

In 3D powder bed fusion additive manufacturing, known sourced anddesignated powders are preferred or required. This may be motivated by anumber of reasons including (1) better print quality due to the powderedmaterial meeting specifications tailored to the specific printer, (2)better audit trail of the powdered material composition and higherprobability that it is free of defects, (3) protection of the printerfrom contaminants which might break the printer or cause more warrantyrepair, or (4) higher revenues and margins from sales of designatedpowdered materials. Interests of customers and powder suppliers maydiverge when customers wish to use non-authorized powdered materials ina given printer. Furthermore, if a powdered material is re-used,characteristics of the powdered material could change overtime such asparticle size distribution and density. The elemental/alloy compositionof a powdered material due to thermal cycling and oxidation may bealtered during a print cycle. To most accurately account for thesechanges of a powdered material, the powder bed fusion additivemanufacturing process may need to be adjusted periodically during aprint process to improve the quality of printed objects.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present disclosureare described with reference to the following figures, wherein likereference numerals refer to like parts throughout the various figuresunless otherwise specified.

FIG. 1A illustrates an additive manufacturing system;

FIG. 1B is a top view of a structure being formed on an additivemanufacturing system;

FIG. 2 illustrates an additive manufacturing method;

FIG. 3A is a cartoon illustrating an additive manufacturing systemincluding lasers;

FIG. 3B is a detailed description of the light patterning unit shown inFIG. 3A;

FIG. 3C is one embodiment of an additive manufacturing system with a“switchyard” for directing and repatterning light using multiple imagerelays;

FIG. 3D illustrates a simple mirror image pixel remapping;

FIG. 3E illustrates a series of image transforming image relays forpixel remapping; FIG. 3F illustrates an patternable electron energy beamadditive manufacturing system;

FIG. 3G illustrates a detailed description of the electron beampatterning unit shown in FIG. 3F;

FIG. 4 is a block diagram depicting an example apparatus of an ingestersystem in accordance with an embodiment of the present disclosure.

FIG. 5 is a flowchart depicting an example process of in-processcollection and sampling of powder samples in accordance with anembodiment of the present disclosure.

FIG. 6 is an example implementation of an ingester system used in powderbed fusion additive manufacturing in accordance with an embodiment ofthe present disclosure.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings that form a part thereof, and in which is shown by way ofillustrating specific exemplary embodiments in which the disclosure maybe practiced. These embodiments are described in sufficient detail toenable those skilled in the art to practice the concepts disclosedherein, and it is to be understood that modifications to the variousdisclosed embodiments may be made, and other embodiments may beutilized, without departing from the scope of the present disclosure.The following detailed description is, therefore, not to be taken in alimiting sense.

The present disclosure describes an ingester system used in powder bedfusion additive manufacturing that collects in-process (in real-time orin-situ) powder samples and performs a set of characterizations on thepowder samples.

In various embodiments in accordance with the present disclosure, aningester system may collect powder samples periodically at apredetermined interval during a print process. The powder samples may bestored for analysis later or may be characterized in real-time tounderstand changes of characteristics of the powders during the printprocess. The characterization results may determine whether to abort theprint process or adjust printing parameters associated with powder bedfusion additive printing.

In some embodiments, powder samples may be collected and stored forlater off-site analysis. This approach may help with diagnostics onproperties of the printed object, audit of powder quality, consistencyfrom powder suppliers as well as potential contract violation(s) by acustomer using unauthorized powdered materials on the printer.

In another embodiment, a method of identifying unlicensed powder usagein an additive manufacturing system involves collecting a plurality ofpowder samples of a powdered material in real-time during a print job.The collected powder samples are used for audit and authorization byperforming at least one of the following steps: i) storing the collectedpowder samples for later characterization; and ii) immediatelycharacterizing the powder samples to determine whether to abort theprint job according to a result of the set of characterizations.

An additive manufacturing system is disclosed which has one or moreenergy sources, including in one embodiment, one or more laser orelectron beams, positioned to emit one or more energy beams. Beamshaping optics may receive the one or more energy beams from the energysource and form a single beam. An energy patterning unit receives orgenerates the single beam and transfers a two-dimensional pattern to thebeam, and may reject the unused energy not in the pattern. An imagerelay receives the two-dimensional patterned beam and focuses it as atwo-dimensional image to a desired location on a height fixed or movablebuild platform (e.g. a powder bed). In certain embodiments, some or allof any rejected energy from the energy patterning unit is reused.

In some embodiments, multiple beams from the laser array(s) are combinedusing a beam homogenizer. This combined beam can be directed at anenergy patterning unit that includes either a transmissive or reflectivepixel addressable light valve. In one embodiment, the pixel addressablelight valve includes both a liquid crystal module having a polarizingelement and a light projection unit providing a two-dimensional inputpattern. The two-dimensional image focused by the image relay can besequentially directed toward multiple locations on a powder bed to builda 3D structure.

As seen in FIG. 1, an additive manufacturing system 100 has an energypatterning system 110 with an energy source 112 that can direct one ormore continuous or intermittent energy beam(s) toward beam shapingoptics 114. After shaping, if necessary, the beam is patterned by anenergy patterning unit 116, with generally some energy being directed toa rejected energy handling unit 118. Patterned energy is relayed byimage relay 120 toward an article processing unit 140, typically as atwo-dimensional image 122 focused near a bed 146. The bed 146 (withoptional walls 148) can form a chamber containing material 144 dispensedby material dispenser 142. Patterned energy, directed by the image relay120, can melt, fuse, sinter, amalgamate, change crystal structure,influence stress patterns, or otherwise chemically or physically modifythe dispensed material 144 to form structures with desired properties.

Energy source 112 generates photon (light), electron, ion, or othersuitable energy beams or fluxes capable of being directed, shaped, andpatterned. Multiple energy sources can be used in combination. Theenergy source 112 can include lasers, incandescent light, concentratedsolar, other light sources, electron beams, or ion beams. Possible lasertypes include, but are not limited to: Gas Lasers, Chemical Lasers, DyeLasers, Metal Vapor Lasers, Solid State Lasers (e.g. fiber),Semiconductor (e.g. diode) Lasers, Free electron laser, Gas dynamiclaser, “Nickel-like” Samarium laser, Raman laser, or Nuclear pumpedlaser.

A Gas Laser can include lasers such as a Helium-neon laser, Argon laser,Krypton laser, Xenon ion laser, Nitrogen laser, Carbon dioxide laser,Carbon monoxide laser or Excimer laser.

A Chemical laser can include lasers such as a Hydrogen fluoride laser,Deuterium fluoride laser, COIL (Chemical oxygen-iodine laser), or Agil(All gas-phase iodine laser).

A Metal Vapor Laser can include lasers such as a Helium-cadmium (HeCd)metal-vapor laser, Helium-mercury (HeHg) metal-vapor laser,Helium-selenium (HeSe) metal-vapor laser, Helium-silver (HeAg)metal-vapor laser, Strontium Vapor Laser, Neon-copper (NeCu) metal-vaporlaser, Copper vapor laser, Gold vapor laser, or Manganese (Mn/MnCl₂)vapor laser.

A Solid State Laser can include lasers such as a Ruby laser, Nd:YAGlaser, NdCrYAG laser, Er:YAG laser, Neodymium YLF (Nd:YLF) solid-statelaser, Neodymium doped Yttrium orthovanadate(Nd:YVO₄) laser, Neodymiumdoped yttrium calcium oxoborateNd:YCa₄O(BO₃)³ or simply Nd:YCOB,Neodymium glass(Nd:Glass) laser, Titanium sapphire(Ti:sapphire) laser,Thulium YAG (Tm:YAG) laser, Ytterbium YAG (Yb:YAG) laser, Ytterbium:2O₃(glass or ceramics) laser, Ytterbium doped glass laser (rod, plate/chip,and fiber), Holmium YAG (Ho:YAG) laser, Chromium ZnSe (Cr:ZnSe) laser,Cerium doped lithium strontium (or calcium)aluminum fluoride(Ce:LiSAF,Ce:LiCAF), Promethium 147 doped phosphate glass(147Pm⁺³:Glass)solid-state laser, Chromium doped chrysoberyl (alexandrite) laser,Erbium doped anderbium-ytterbium co-doped glass lasers, Trivalenturanium doped calcium fluoride (U:CaF₂) solid-state laser, Divalentsamarium doped calcium fluoride(Sm:CaF₂) laser, or F-Center laser.

A Semiconductor Laser can include laser medium types such as GaN, InGaN,AlGaInP, AlGaAs, InGaAsP, GaInP, InGaAs, InGaAsO, GaInAsSb, lead salt,Vertical cavity surface emitting laser (VCSEL), Quantum cascade laser,Hybrid silicon laser, or combinations thereof.

For example, in one embodiment a single Nd:YAG q-switched laser can beused in conjunction with multiple semiconductor lasers. In anotherembodiment, an electron beam can be used in conjunction with anultraviolet semiconductor laser array. In still other embodiments, atwo-dimensional array of lasers can be used. In some embodiments withmultiple energy sources, pre-patterning of an energy beam can be done byselectively activating and deactivating energy sources.

Beam shaping unit 114 can include a great variety of imaging optics tocombine, focus, diverge, reflect, refract, homogenize, adjust intensity,adjust frequency, or otherwise shape and direct one or more energy beamsreceived from the energy source 112 toward the energy patterning unit116. In one embodiment, multiple light beams, each having a distinctlight wavelength, can be combined using wavelength selective mirrors(e.g. dichroics) or diffractive elements. In other embodiments, multiplebeams can be homogenized or combined using multifaceted mirrors,microlenses, and refractive or diffractive optical elements.

Energy patterning unit 116 can include static or dynamic energypatterning elements. For example, photon, electron, or ion beams can beblocked by masks with fixed or movable elements. To increase flexibilityand ease of image patterning, pixel addressable masking, imagegeneration, or transmission can be used. In some embodiments, the energypatterning unit includes addressable light valves, alone or inconjunction with other patterning mechanisms to provide patterning. Thelight valves can be transmissive, reflective, or use a combination oftransmissive and reflective elements. Patterns can be dynamicallymodified using electrical or optical addressing. In one embodiment, atransmissive optically addressed light valve acts to rotate polarizationof light passing through the valve, with optically addressed pixelsforming patterns defined by a light projection source. In anotherembodiment, a reflective optically addressed light valve includes awrite beam for modifying polarization of a read beam. In yet anotherembodiment, an electron patterning device receives an address patternfrom an electrical or photon stimulation source and generates apatterned emission of electrons.

Rejected energy handling unit 118 is used to disperse, redirect, orutilize energy not patterned and passed through the energy pattern imagerelay 120. In one embodiment, the rejected energy handling unit 118 caninclude passive or active cooling elements that remove heat from theenergy patterning unit 116. In other embodiments, the rejected energyhandling unit can include a “beam dump” to absorb and convert to heatany beam energy not used in defining the energy pattern. In still otherembodiments, rejected beam energy can be recycled using beam shapingoptics 114. Alternatively, or in addition, rejected beam energy can bedirected to the article processing unit 140 for heating or furtherpatterning. In certain embodiments, rejected beam energy can be directedto additional energy patterning systems or article processing units.

Image relay 120 receives a patterned image (typically two-dimensional)from the energy patterning unit 116 and guides it toward the articleprocessing unit 140. In a manner similar to beam shaping optics 114, theimage relay 120 can include optics to combine, focus, diverge, reflect,refract, adjust intensity, adjust frequency, or otherwise shape anddirect the patterned image.

Article processing unit 140 can include a walled chamber 148 and bed144, and a material dispenser 142 for distributing material. Thematerial dispenser 142 can distribute, remove, mix, provide gradationsor changes in material type or particle size, or adjust layer thicknessof material. The material can include metal, ceramic, glass, polymericpowders, other melt-able material capable of undergoing a thermallyinduced phase change from solid to liquid and back again, orcombinations thereof. The material can further include composites ofmelt-able material and non-melt-able material where either or bothcomponents can be selectively targeted by the imaging relay system tomelt the component that is melt-able, while either leaving along thenon-melt-able material or causing it to undergo avaporizing/destroying/combusting or otherwise destructive process. Incertain embodiments, slurries, sprays, coatings, wires, strips, orsheets of materials can be used. Unwanted material can be removed fordisposable or recycling by use of blowers, vacuum systems, sweeping,vibrating, shaking, tipping, or inversion of the bed 146.

In addition to material handling components, the article processing unit140 can include components for holding and supporting 3D structures,mechanisms for heating or cooling the chamber, auxiliary or supportingoptics, and sensors and control mechanisms for monitoring or adjustingmaterial or environmental conditions. The article processing unit can,in whole or in part, support a vacuum or inert gas atmosphere to reduceunwanted chemical interactions as well as to mitigate the risks of fireor explosion (especially with reactive metals).

Control processor 150 can be connected to control any components ofadditive manufacturing system 100. The control processor 150 can beconnected to variety of sensors, actuators, heating or cooling systems,monitors, and controllers to coordinate operation. A wide range ofsensors, including imagers, light intensity monitors, thermal, pressure,or gas sensors can be used to provide information used in control ormonitoring. The control processor can be a single central controller, oralternatively, can include one or more independent control systems. Thecontroller processor 150 is provided with an interface to allow input ofmanufacturing instructions. Use of a wide range of sensors allowsvarious feedback control mechanisms that improve quality, manufacturingthroughput, and energy efficiency.

FIG. 1B is a cartoon illustrating a bed 146 that supports material 144.Using a series of sequentially applied, two-dimensional patterned energybeam images (squares in dotted outline 124), a structure 149 isadditively manufactured. As will be understood, image patterns havingnon-square boundaries can be used, overlapping or interpenetratingimages can be used, and images can be provided by two or more energypatterning systems. In other embodiments, images can be formed inconjunction with directed electron or ion beams, or with printed orselective spray systems.

FIG. 2 is a flow chart illustrating one embodiment of an additivemanufacturing process supported by the described optical and mechanicalcomponents. In step 202, material is positioned in a bed, chamber, orother suitable support. The material can be a powder capable of beingmelted, fused, sintered, induced to change crystal structure, havestress patterns influenced, or otherwise chemically or physicallymodified to form structures with desired properties.

In step 204, unpatterned energy is emitted by one or more energyemitters, including but not limited to solid state or semiconductorlasers, or electrical power supply flowing electrons down a wire. Instep 206, the unpatterned energy is shaped and modified (e.g. intensitymodulated or focused). In step 208, this unpatterned energy ispatterned, with energy not forming a part of the pattern being handledin step 210 (this can include conversion to waste heat, or recycling aspatterned or unpatterned energy). In step 212, the patterned energy, nowforming a two-dimensional image is relayed toward the material. In step214, the image is applied to the material, building a portion of a 3Dstructure. These steps can be repeated (loop 218) until the image (ordifferent and subsequent image) has been applied to all necessaryregions of a top layer of the material. When application of energy tothe top layer of the material is finished, a new layer can be applied(loop 216) to continue building the 3D structure. These process loopsare continued until the 3D structure is complete, when remaining excessmaterial can be removed or recycled.

FIG. 3A is one embodiment of an additive manufacturing system 300 thatuses multiple semiconductor lasers as part of an energy patterningsystem 310. A control processor 350 can be connected to variety ofsensors, actuators, heating or cooling systems, monitors, andcontrollers to coordinate operation of multiple lasers 312, lightpatterning unit 316, and image relay 320, as well as any other componentof system 300. These connections are generally indicated by a dottedoutline 351 surrounding components of system 300. As will beappreciated, connections can be wired or wireless, continuous orintermittent, and include capability for feedback (for example, thermalheating can be adjusted in response to sensed temperature). The multiplelasers 312 can emit a beam 301 of light at a 1000 nm wavelength that,for example, is 90 mm wide by 20 mm tall. The beam 301 is resized byimaging optics 370 to create beam 303. Beam 303 is 6 mm wide by 6 mmtall, and is incident on light homogenization device 372 which blendslight together to create blended beam 305. Beam 305 is then incident onimaging assembly 374 which reshapes the light into beam 307 and is thenincident on hot cold mirror 376. The mirror 376 allows 1000 nm light topass, but reflects 450 nm light. A light projector 378 capable ofprojecting low power light at 1080p pixel resolution and 450 nm emitsbeam 309, which is then incident on hot cold mirror 376. Beams 307 and309 overlay in beam 311, and both are imaged onto optically addressedlight valve 380 in a 20 mm wide, 20 mm tall image. Images formed fromthe homogenizer 372 and the projector 378 are recreated and overlaid onlight valve 380.

The optically addressed light valve 380 is stimulated by the light(typically ranging from 400-500 nm) and imprints a polarization rotationpattern in transmitted beam 313 which is incident upon polarizer 382.The polarizer 382 splits the two polarization states, transmittingp-polarization into beam 317 and reflecting s-polarization into beam 315which is then sent to a beam dump 318 that handles the rejected energy.As will be understood, in other embodiments the polarization could bereversed, with s-polarization formed into beam 317 and reflectingp-polarization into beam 315. Beam 317 enters the final imaging assembly320 which includes optics 384 that resize the patterned light. This beamreflects off of a movable mirror 386 to beam 319, which terminates in afocused image applied to material bed 344 in an article processing unit340. The depth of field in the image selected to span multiple layers,providing optimum focus in the range of a few layers of error or offset.

The bed 390 can be raised or lowered (vertically indexed) within chamberwalls 388 that contain material 344 dispensed by material dispenser 342.In certain embodiments, the bed 390 can remain fixed, and optics of thefinal imaging assembly 320 can be vertically raised or lowered. Materialdistribution is provided by a sweeper mechanism 392 that can evenlyspread powder held in hopper 394, being able to provide new layers ofmaterial as needed. An image 6 mm wide by 6 mm tall can be sequentiallydirected by the movable mirror 386 at different positions of the bed.

When using a powdered ceramic or metal material in this additivemanufacturing system 300, the powder can be spread in a thin layer,approximately 1-3 particles thick, on top of a base substrate (andsubsequent layers) as the part is built. When the powder is melted,sintered, or fused by a patterned beam 319, it bonds to the underlyinglayer, creating a solid structure. The patterned beam 319 can beoperated in a pulsed fashion at 40 Hz, moving to the subsequent 6 mm×6mm image locations at intervals of 10 ms to 0.5 ms (with 3 to 0.1 msbeing desirable) until the selected patterned areas of powder have beenmelted. The bed 390 then lowers itself by a thickness corresponding toone layer, and the sweeper mechanism 392 spreads a new layer of powderedmaterial. This process is repeated until the 2D layers have built up thedesired 3D structure. In certain embodiments, the article processingunit 340 can have a controlled atmosphere. This allows reactivematerials to be manufactured in an inert gas, or vacuum environmentwithout the risk of oxidation or chemical reaction, or fire or explosion(if reactive metals are used).

FIG. 3B illustrates in more detail operation of the light patterningunit 316 of FIG. 3A. As seen in FIG. 3B, a representative input pattern333 (here seen as the numeral “9”) is defined in an 8×12 pixel array oflight projected as beam 309 toward mirror 376. Each grey pixelrepresents a light filled pixel, while white pixels are unlit. Inpractice, each pixel can have varying levels of light, includinglight-free, partial light intensity, or maximal light intensity.Unpatterned light 331 that forms beam 307 is directed and passes througha hot/cold mirror 376, where it combines with patterned beam 309. Afterreflection by the hot/cold mirror 376, the patterned light beam 311formed from overlay of beams 307 and 309 in beam 311, and both areimaged onto optically addressed light valve 380. The optically addressedlight valve 380, which would rotate the polarization state ofunpatterned light 331, is stimulated by the patterned light beam 309,311 to selectively not rotate the polarization state of polarized light307, 311 in the pattern of the numeral “9” into beam 313. The unrotatedlight representative of pattern 333 in beam 313 is then allowed to passthrough polarizer mirror 382 resulting in beam 317 and pattern 335.Polarized light in a second rotated state is rejected by polarizermirror 382, into beam 315 carrying the negative pixel pattern 337consisting of a light-free numeral “9”.

Other types of light valves can be substituted or used in combinationwith the described light valve. Reflective light valves, or light valvesbase on selective diffraction or refraction can also be used. In certainembodiments, non-optically addressed light valves can be used. These caninclude but are not limited to electrically addressable pixel elements,movable mirror or micro-mirror systems, piezo or micro-actuated opticalsystems, fixed or movable masks, or shields, or any other conventionalsystem able to provide high intensity light patterning. For electronbeam patterning, these valves may selectively emit electrons based on anaddress location, thus imbuing a pattern on the beam of electronsleaving the valve.

FIG. 3C is one embodiment of an additive manufacturing system thatincludes a switchyard system enabling reuse of patterned two-dimensionalenergy. Similar to the embodiment discussed with respect to FIG. 1A, anadditive manufacturing system 220 has an energy patterning system withan energy source 112 that directs one or more continuous or intermittentenergy beam(s) toward beam shaping optics 114. After shaping, the beamis two-dimensionally patterned by an energy patterning unit 230, withgenerally some energy being directed to a rejected energy handling unit222. Patterned energy is relayed by one of multiple image relays 232toward one or more article processing units 234A, 234B, 234C, or 234D,typically as a two-dimensional image focused near a movable or fixedheight bed. The bed (with optional walls) can form a chamber containingmaterial dispensed by material dispenser. Patterned energy, directed bythe image relays 232, can melt, fuse, sinter, amalgamate, change crystalstructure, influence stress patterns, or otherwise chemically orphysically modify the dispensed material to form structures with desiredproperties.

In this embodiment, the rejected energy handling unit has multiplecomponents to permit reuse of rejected patterned energy. Relays 228A,228B, and 22C can respectively transfer energy to an electricitygenerator 224, a heat/cool thermal management system 225, or an energydump 226. Optionally, relay 228C can direct patterned energy into theimage relay 232 for further processing. In other embodiments, patternedenergy can be directed by relay 228C, to relay 228B and 228A forinsertion into the energy beam(s) provided by energy source 112. Reuseof patterned images is also possible using image relay 232. Images canbe redirected, inverted, mirrored, sub-patterned, or otherwisetransformed for distribution to one or more article processing units.234A-D. Advantageously, reuse of the patterned light can improve energyefficiency of the additive manufacturing process, and in some casesimprove energy intensity directed at a bed, or reduce manufacture time.

FIG. 3D is a cartoon 235 illustrating a simple geometricaltransformation of a rejected energy beam for reuse. An input pattern 236is directed into an image relay 237 capable of providing a mirror imagepixel pattern 238. As will be appreciated, more complex pixeltransformations are possible, including geometrical transformations, orpattern remapping of individual pixels and groups of pixels. Instead ofbeing wasted in a beam dump, this remapped pattern can be directed to anarticle processing unit to improve manufacturing throughput or beamintensity.

FIG. 3E is a cartoon 235 illustrating multiple transformations of arejected energy beam for reuse. An input pattern 236 is directed into aseries of image relays 237B-E capable of providing a pixel pattern 238.

FIGS. 3F and 3G illustrates a non-light based energy beam system 240that includes a patterned electron beam 241 capable of producing, forexample, a “P” shaped pixel image. A high voltage electricity powersystem 243 is connected to an optically addressable patterned cathodeunit 245. In response to application of a two-dimensional patternedimage by projector 244, the cathode unit 245 is stimulated to emitelectrons wherever the patterned image is optically addressed. Focusingof the electron beam pattern is provided by an image relay system 247that includes imaging coils 246A and 246B. Final positioning of thepatterned image is provided by a deflection coil 248 that is able tomove the patterned image to a desired position on a bed of additivemanufacturing component 249.

In another embodiment supporting light recycling and reuse, multiplexmultiple beams of light from one or more light sources are provided. Themultiple beams of light may be reshaped and blended to provide a firstbeam of light. A spatial polarization pattern may be applied on thefirst beam of light to provide a second beam of light. Polarizationstates of the second beam of light may be split to reflect a third beamof light, which may be reshaped into a fourth beam of light. The fourthbeam of light may be introduced as one of the multiple beams of light toresult in a fifth beam of light. In effect, this or similar systems canreduce energy costs associated with an additive manufacturing system. Bycollecting, beam combining, homogenizing and re-introducing unwantedlight rejected by a spatial polarization valve or light valve operatingin polarization modification mode, overall transmitted light power canpotentially be unaffected by the pattern applied by a light valve. Thisadvantageously results in an effective re-distribution of the lightpassing through the light valve into the desired pattern, increasing thelight intensity proportional to the amount of area patterned.

Combining beams from multiple lasers into a single beam is one way toincreasing beam intensity. In one embodiment, multiple light beams, eachhaving a distinct light wavelength, can be combined using eitherwavelength selective mirrors or diffractive elements. In certainembodiments, reflective optical elements that are not sensitive towavelength dependent refractive effects can be used to guide amultiwavelength beam.

Patterned light can be directed using movable mirrors, prisms,diffractive optical elements, or solid state optical systems that do notrequire substantial physical movement. In one embodiment, amagnification ratio and an image distance associated with an intensityand a pixel size of an incident light on a location of a top surface ofa powder bed can be determined for an additively manufactured,three-dimensional (3D) print job. One of a plurality of lens assembliescan be configured to provide the incident light having the magnificationratio, with the lens assemblies both a first set of optical lenses and asecond sets of optical lenses, and with the second sets of opticallenses being swappable from the lens assemblies. Rotations of one ormore sets of mirrors mounted on compensating gantries and a final mirrormounted on a build platform gantry can be used to direct the incidentlight from a precursor mirror onto the location of the top surface ofthe powder bed. Translational movements of compensating gantries and thebuild platform gantry are also able to ensure that distance of theincident light from the precursor mirror to the location of the topsurface of the powder bed is substantially equivalent to the imagedistance. In effect, this enables a quick change in the optical beamdelivery size and intensity across locations of a build area fordifferent powdered materials while ensuring high availability of thesystem.

In certain embodiments, a plurality of build chambers, each having abuild platform to hold a powder bed, can be used in conjunction withmultiple optical-mechanical assemblies arranged to receive and directthe one or more incident energy beams into the build chambers. Multiplechambers allow for concurrent printing of one or more print jobs insideone or more build chambers. In other embodiments, a removable chambersidewall can simplify removal of printed objects from build chambers,allowing quick exchanges of powdered materials. The chamber can also beequipped with an adjustable process temperature controls.

In another embodiment, one or more build chambers can have a buildchamber that is maintained at a fixed height, while optics arevertically movable. A distance between final optics of a lens assemblyand a top surface of powder bed a may be managed to be essentiallyconstant by indexing final optics upwards, by a distance equivalent to athickness of a powder layer, while keeping the build platform at a fixedheight. Advantageously, as compared to a vertically moving the buildplatform, large and heavy objects can be more easily manufactured, sinceprecise micron scale movements of the build platform are not needed.Typically, build chambers intended for metal powders with a volume morethan ˜0.1-0.2 cubic meters (i.e., greater than 100-200 liters or heavierthan 500-1,000 kg) will most benefit from keeping the build platform ata fixed height.

In one embodiment, a portion of the layer of the powder bed may beselectively melted or fused to form one or more temporary walls out ofthe fused portion of the layer of the powder bed to contain anotherportion of the layer of the powder bed on the build platform. Inselected embodiments, a fluid passageway can be formed in the one ormore first walls to enable improved thermal management.

Improved powder handling can be another aspect of an improved additivemanufacturing system. A build platform supporting a powder bed can becapable of tilting, inverting, and shaking to separate the powder bedsubstantially from the build platform in a hopper. The powdered materialforming the powder bed may be collected in a hopper for reuse in laterprint jobs. The powder collecting process may be automated, andvacuuming or gas jet systems also used to aid powder dislodgement andremoval

Some embodiments of the disclosed additive manufacturing system can beconfigured to easily handle parts longer than an available chamber. Acontinuous (long) part can be sequentially advanced in a longitudinaldirection from a first zone to a second zone. In the first zone,selected granules of a granular material can be amalgamated. In thesecond zone, unamalgamated granules of the granular material can beremoved. The first portion of the continuous part can be advanced fromthe second zone to a third zone, while a last portion of the continuouspart is formed within the first zone and the first portion is maintainedin the same position in the lateral and transverse directions that thefirst portion occupied within the first zone and the second zone. Ineffect, additive manufacture and clean-up (e.g., separation and/orreclamation of unused or unamalgamated granular material) may beperformed in parallel (i.e., at the same time) at different locations orzones on a part conveyor, with no need to stop for removal of granularmaterial and/or parts.

In another embodiment, additive manufacturing capability can be improvedby use of an enclosure restricting an exchange of gaseous matter betweenan interior of the enclosure and an exterior of the enclosure. Anairlock provides an interface between the interior and the exterior;with the interior having multiple additive manufacturing chambers,including those supporting power bed fusion. A gas management systemmaintains gaseous oxygen within the interior at or below a limitingoxygen concentration, increasing flexibility in types of powder andprocessing that can be used in the system.

In another manufacturing embodiment, capability can be improved byhaving a 3D printer contained within an enclosure, the printer able tocreate a part having a weight greater than or equal to 2,000 kilograms.A gas management system may maintain gaseous oxygen within the enclosureat concentrations below the atmospheric level. In some embodiments, awheeled vehicle may transport the part from inside the enclosure,through an airlock, since the airlock operates to buffer between agaseous environment within the enclosure and a gaseous environmentoutside the enclosure, and to a location exterior to both the enclosureand the airlock.

Other manufacturing embodiments involve collecting powder samples inreal-time in a powder bed fusion additive manufacturing system. Aningester system is used for in-process collection and characterizationsof powder samples. The collection may be performed periodically and theresults of characterizations result in adjustments to the powder bedfusion process. The ingester system can optionally be used for one ormore of audit, process adjustments or actions such as modifying printerparameters or verifying proper use of licensed powder materials.

Yet another improvement to an additive manufacturing process can beprovided by use of a manipulator device such as a crane, lifting gantry,robot arm, or similar that allows for the manipulation of parts thatwould be difficult or impossible for a human to move is described. Themanipulator device can grasp various permanent or temporary additivelymanufactured manipulation points on a part to enable repositioning ormaneuvering of the part.

FIG. 4 is a block diagram illustrating an example apparatus 400including ingester system 410 in accordance with an embodiment of thepresent disclosure. Ingester system 410 may perform various functionsrelated to techniques, methods and systems described herein, includingthose described below with respect to process 500 and implementation600. Ingester system 410 may be installed in, equipped on, connected toor otherwise implemented in a powder bed fusion additive manufacturingsystem (such as that shown in FIGS. 1A, 1B, 2, 3A and 3B) to effectvarious embodiments in accordance with the present disclosure. Ingestersystem 410 may include at least some of the components illustrated inFIG. 4.

In some embodiments, ingester system 410 may involve ingester 420collecting powder samples of a powdered material during powder bedfusion additive manufacturing. The powdered material may include metal,ceramic, plastic powders, or other suitable powders able to bondtogether while subjected to a thermal energy. The collection of powdersamples may be performed periodically at a predetermined interval. Thepowder samples may be collected or taken by ingester 420 from the powderbed or the powder distribution system such as powder dispensing assembly470. A mechanical assembly such as a scoop, diverter, or mechanical armmay be used to collect or pick up powder samples at predeterminedlocations.

In some embodiments, ingester system 410 may include storage container450 capable of packaging the powder samples in a plurality of samplecanister 460(1)-460(N), with N being a positive integer greater than 0.The sample canister 460(1)-460(N) may be stored for analyses that maynot be suitable for in-process (in real-time or in-situ)characterization or for auditing purposes later. Storage container 450may be capable of packaging powder samples in an atmospheresubstantially equivalent to an in-process atmosphere inside samplecanister 460(1)-460(N). The atmosphere may be air or an inert gas suchas nitrogen, argon or helium.

In some embodiments, ingester system 410 may include test suite 430capable of performing test 440(1)-440(K), with K being a positiveinteger. Test suite 430 may be a collection of instruments havingcapabilities to perform one or more tests of test 440(1)-440(K). Forexample, the collection of instruments may include dilatometer, flashdiffusivity analyzer, gas chromatography mass spectrometry, gaspycnometer, inclinometer, particle size analyzer, particle shapeanalyzer, profilometer, scale, spectrometer, thermometer, tintometer, orother instruments capable of measuring properties or qualities ofpowders. Test 440(1)-440(K) may perform characterizations of powdersamples on one or more specific properties respectively. The one or morespecific properties of powder samples may include thermal diffusivity,density, surface roughness, weight, emissivity, absorptivity,reflectance, transmissivity, temperature, color, and particle sizedistribution. The one or more qualities of powder samples may includeuniformity of particle size, uniformity of composition, or uniformity ofsurface roughness. Some powdered materials may have undergone undesiredchanges after a print cycle with inadequate processing conditions orthermal cycles. The inadequate processing conditions may includenon-uniform thicknesses of a powder layer dispensed by powder dispensingassembly 470, an excessive temperature of a powder bed caused by anoverheating of build platform 490, or an incident beam having anintensity too high. The results of characterization may be used toadjust printing parameters during a print process to improve printquality. The printing parameters may include a rate of dispensing tocontrol a thickness uniformity, a temperature of built platform 490, andan intensity or dwell time (duration) of an incident beam to control adimension, a pulse shape of energy source incident on the powdermaterial modulated over time and position on the bed, and one or morespecific electrical, mechanical, or optical properties of a printedobject.

In some embodiments, the result of characterizations performed by Test440(1)-440(K) may indicate significant alternation of one or more powderproperties and beyond the range of workable specifications. The printprocess may be aborted in such conditions.

Ingester system 410 may include processor 401 and memory 402. Processor401 may be coupled to memory 402 to access data stored therein and toexecute any programs/instructions stored therein. Processor 701 maycontrol ingester system 410 performing powder sample collection at apredetermined interval. Processor 401 may execute instructions as towhich test of test 440(1)-440(K) in test suite 430 may be performed.Processor 401 may further control storage container 450 packaging thepowder samples in sample canister 460(1)-460(N). The result of test440(1)-440(K) may be stored in memory 402.

Example apparatus 400 may include components of a powder bed fusionadditive manufacturing system such as powder dispensing assembly 470,print head 480, and build platform 490. Powder dispensing assembly 470may dispense a plurality of layers of a powdered material to form apowder bed supported by build platform 490. Print head 480 may includean energy source (e.g., fiber laser or diode laser) capable of providinga light beam of sufficient energy to melt/sinter the powdered material.Build platform 490 may have resistive heating elements inside to controla temperature of a powder bed formed by layers of a powdered material.Processor 401 may control powder dispensing assembly 470, print head480, and build platform 490 in response to characterization results ofpowder samples by ingester system 410 during a print process.

FIG. 5 illustrates an example process 500 of collecting andcharacterizing powder samples of a powdered material during a printprocess. Process 500 may be utilized to collect the powder samples froma powder bed or a powder distribution assembly, and characterizing thepowder samples in real-time in a test suite in accordance with thepresent disclosure. Process 500 may include one or more operations,actions, or functions shown as blocks such as 510, 520, 530, and 540.Although illustrated as discrete blocks, various blocks of process 500may be divided into additional blocks, combined into fewer blocks, oreliminated, depending on the desired implementation, and may beperformed or otherwise carried out in an order different from that shownin FIG. 5. Process 500 may be implemented in example implementation 600,and may be implemented by example apparatus 400 described above. Forillustrative purposes and without limiting the scope, the followingdescription of process 500 is provided in the context of exampleimplementation 600 as being implemented by example apparatus 400.Process 500 may begin with block 510.

At 510, process 500 may involve processor 401 of example apparatus 400controlling ingester 420 to collect a plurality of powder samples of apowdered material in forming a printed object during a print cycle. Thepowdered material may include metal, ceramic, plastic powders, or othersuitable powders able to bond together while subjected to a thermalenergy. At 510, processor 401 may instruct ingester 420 collectingpowder samples periodically at a predetermined interval or randomly orat predetermined stages during a print process. For example, processor401 may instruct ingester 420 to collect powder samples at every10-minute interval or only at ⅕th and ⅘th completion of a print process.Ingester 420 may have a mechanism for diverting incoming powder from apowder bed or powder dispensing assembly 470 of example apparatus 400.Ingester 420 may also control an amount of powders being diverted,depending how many tests are required for analysis. Process 500 mayproceed from 510 to 520.

At 520, process 500 may involve processor 401 controlling test suite 430to perform one or more tests of test 440(1)-440(K). In some embodiments,one or more specific properties of a powdered material may need to betightly controlled within a certain range to guarantee the mechanical,electrical, or optical properties of the printed object. In otherembodiments, characteristics of powders during a print process may needto be retained for auditing purposes. Test suite 430 may includeinstruments having capabilities to perform one or more tests of test440(1)-440(K). For illustrating purposes and without limitation, test440(1) may measure a distribution of powder sizes by particle sizeanalyzer; test 440(2) may measure a density of powder samples bypycnometer; test 440(3) may identify substances within the powdersamples by gas chromatography mass spectrometry. Some exampleinstruments for the possible test suite 430 along with the types of datagathered or property measured are listed, but are not limited to, in thetable below. Process 500 may proceed from 520 to 530.

Example Instrument Data Gathered or Property Measured Dilatometer Volumechanges caused by a physical or chemical process Flash DiffusivityThermal diffusivity Gas Chromatography Mass Identifies differentsubstances within Spectrometry a test sample Gas Pycnometer Volume anddensity of solids Inclinometer Angle of a slope Particle Size AnalyzerDistribution of particle sizes Particle Shape Analyzer Distribution ofparticle shapes Profilometer Surface roughness Scale Weight SpectrometerEmissivity, Absorptivity, Reflectance, Transmissivity ThermometerTemperature Tintometer Color

At 530, process 500 may involve processor 401 determining whether tomodify a set of printing parameters employed for the print process orwhether to abort the print process according to a resultcharacterization from test 440(1)-440(K). The determination may includecomputer simulations by processor 401 based on a set of models usingresults of the characterizations as input. Powder samples may haveundergone undesired changes for powders without certification orinadequate processing conditions. Test 440(1)-440(K) may provide areal-time feedback on the properties of powders during the printprocess. Processor 401 may determine to modify one or more printingparameters according characterization results of test 440(1)-440(K). Forexample, processor 401 may increase or decrease the incident beamintensity provided by print head 480 when gas pycnometer measures adeviation of specified powder density which may affect the energy perunit volume required to melt or sinter the powders. Processor 401 mayalso control dwell time of the incident beam provided by print head 480or a thickness of powder layer dispensed by powder dispensing assembly470 to adjust for the energy requirement change. The temperature ofbuild platform 490 may be controlled to alleviate burden of the energysource by processor 401. If the deviation of the energy per unit volumeto the specified powder density is too large, processor 401 maydetermine to abort the print process since the energy source insideprint head 480 may not meet the requirement to melt the powders. Inanother example, contaminations within powder samples may be detected bygas chromatography mass spectroscopy, which may affect one or moreelectrical, mechanical and optical properties of the printed object.Thus, processor 401 may determine to abort the print process in suchsituations. In still other embodiments, the print process can be stoppedif characterization results indicate usage of unlicensed powders ordangerous powders, including unlicensed powders likely to result ininferior additive manufacturing results. The characterization results oftest 440(1)-440(K) may be stored in memory 402.

In some embodiments, prediction of final print quality based on theresults of in-process (in real-time or in-situ) characterizations ofpowder samples may be performed by simulations using a set of models.For example, dimensional controls of the printed object may rely on aresolution of the incident beam and a temperature gradient of powdersacross the boundary of melted region. The melted region may expandbeyond the intended boundary if the temperature does not drop quickenough across the boundary and result in exceeding the tolerance of thedimensional requirement. The temperature gradient may be simulated by aheat transfer model which calculates a heat conduction rate based onproperties of powders such as on the compositions and sizes of powders.If the predicted dimension of a printed object by the simulation modelexceeds the tolerance of dimensional requirement, at 530, processor 401may determine to abort the print process. Process 500 may proceed from530 to 540.

At 540, process 500 may involve storage container 450 of exampleapparatus 400 packaging powder samples in a plurality of sample canister460(1)-460(N). The sample canister 460(1)-460(N) may be stored foranalyses that may not be suitable for in-process characterization or forauditing purposes later. Storage container 450 may be capable ofpackaging powder samples in an atmosphere substantially equivalent tothe in-process (in real-time or in-situ) atmosphere inside samplecanister 460(1)-460(N). The atmosphere may be air or an inert gas suchas nitrogen, carbon dioxide, argon, helium, or other noble gas.

FIG. 6 illustrates an example implementation 600 of collecting powdersamples by ingester system 410 in powder bed fusion additivemanufacturing in accordance with the present disclosure. In FIG. 6,build platform 601 supporting a powder bed 612 in a powder bed fusion 3Dprinter is connected to processor 608 together with ingester system 604.The exemplary powder bed fusion 3D printer may measure 1 m by 1 m and isshown without all its side walls for a purpose of clarity. Printing mayoccur via the action of optical module 602 which directs concentratedlaser beam 613 provided by a print head (not shown in FIG. 6) to thesurface of powder bed 612. The optical module 602 may be included in theprint head in addition to an energy source that provides laser beam 613.Powder bed 612 may be formed by a plurality of powder layers dispensedby powder dispensing assembly 603. The powdered material may includemetal, ceramic, plastic powders or other suitable powders able to bondtogether while subjected to a thermal energy. The processing atmospherefor the powdered material inside the powder bed fusion 3D printer may beair or an inert gas including nitrogen, carbon dioxide, argon, helium,or other noble gas. Ingester system 604 may include ingestion 605, thestorage container 606, and test suite 607. Ingester 605 may collect orpick up powder samples in real-time during a print process from powderbed 612 or powder dispensing assembly 603 periodically, randomly, or atpredetermined stages. A mechanical arm or diverter mechanism may beimplemented as ingester 605 for collecting or picking up powder samplesat predetermined locations or randomly and the amount of powder samplesbeing collected may also be predetermined based on a number of requestedanalyses by users of the powder bed fusion 3D printer. The collectedpowder samples may be packaged in sample canisters by storage container606 for auditing purposes or for later analysis. The storage containedmay have a substantially equivalent atmosphere to the processingatmosphere used for the powder samples. Test suite 607 may performcharacterizations such as those illustrated in test 440(1)-test 440(K)of example apparatus 400 on powder samples in real-time after ingester605 has collected the powder samples. The characterizations performed bytest suite 607 may measure one or more properties or qualities of powdersamples from powder bed 612 or powder dispensing assembly 603 usingexample instruments listed in the table at step 520 of example process500. The one or more properties of powder samples may include thermaldiffusivity, density, surface roughness, weight, emissivity,absorptivity, reflectance, transmissivity, temperature, color, andparticle size distribution. Processor 608 may store the characterizationresult of powder samples in memory 609 or using models in computingfacility 611 with the characterization results as inputs to simulation afinal dimension, and one or more electrical, mechanical, or opticalproperties of a printed object.

The results of simulation may be utilized to determine whether to modifythe printing parameters or abort the print process. Upon determining tomodifying the printing parameters for the printed object during a printprocess, processor 608 may control an intensity and dwell time ofincident beam 613 from the print head, a dispensing rate and a thicknessof powders of powder dispensing assembly 603, and a temperature of buildplatform 601 as well as powder bed 612 to improve the properties orqualities of the printed object according the characterization resultsand simulation feedbacks. If the results of simulation indicate that afinal dimension or one or more electrical, mechanical, or opticalproperties may not meet the requirement or specification of the printedobject, processor 608 may determine to abort the print process. Whetherto modify printing parameters or abort the print process may be alsodetermined by users of powder bed fusion 3D printer based on knowledgeand experience of previous characterization results. Some of tests intest suite 607 may not be suitable for in-process characterization andmay be performed later for an off-site analysis. The processor 608 mayhave connectivity to the outside world via the Internet 610 which underselected circumstances connects to a cloud computing facility 611 withsimulation models, advanced computing, and data storage.

The computer processing of the test data such as those illustrated intest 440(1)-440(K) of powder samples in conjunction with a database andpossibly with the additional use of computer simulation models such asthose describe at 530 in example process 500, enable a range of processadjustments and actions, either separately or in combination.

The class of process adjustments span the range of simple to extremelysophisticated. Two related examples as described in example process 500are that print head 480 of example apparatus 400 may adjust its printcharacteristics such as laser dwell time or intensity in the case ofpowder bed fusion printers, or the powder dispensing assembly 470 mayadjust its powder distribution parameters in terms of dispensing rateand layer thickness, in both cases to realize a more effective andhigher quality printed object. Another example is for the printer toadjust printing parameters based on powder sample analysis for aself-protection of the printer, potentially for the case of reactivematerials, or non-compatible materials used with the machine itself.

The class of actions may include denial of further service because thepowdered material is unauthorized, or that the powdered material maydamage the printer, or a potential fire risk due to trace amounts ofpowdered materials from previous builds mixing and interacting in adangerous manner. The actions may also serve as a trigger for billingand tracking purposes related to customer contracts, either directly forprint services or for service.

A final example combining both process adjustments and actions may be anexemplary scenario of a customer being able to load virtually anypowdered material, from any source into the printer, and the printer mayadjust its printing parameters and print an object using the loadedpowdered material. This could be immensely useful to customers in termsof flexibility and to the ability to use low-cost, high-value powderedmaterials.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is understood that the invention is not to be limited tothe specific embodiments disclosed, and that modifications andembodiments are intended to be included within the scope of the appendedclaims. It is also understood that other embodiments of this inventionmay be practiced in the absence of an element/step not specificallydisclosed herein.

1. A method comprising: initiating a print job in a powder bed fusionadditive manufacturing apparatus including a powder bed according to aset of printing parameters; and while performing the print job in thepowder bed fusion additive manufacturing apparatus: collecting aplurality of powder samples of a powdered material from the powder bedduring performance of the print job; performing a set ofcharacterizations on the plurality of powder samples; (a) modifying theset of printing parameters employed during the print job according to aresult of the set of characterizations; and continuing performing theprint job according to the set of printing parameters as modified in(a).
 2. The method of claim 1, wherein: the powder bed fusion additivemanufacturing apparatus comprises a laser configured to selectively meltthe powdered material in the powder bed; and the set of printingparameters include an intensity of a beam emitted by the laser.
 3. Themethod of claim 1, wherein: the powder bed fusion additive manufacturingapparatus comprises a laser configured to selectively melt the powderedmaterial in the powder bed; and the set of printing parameters include adwell time of a beam emitted by the laser on the powdered material inthe powder bed.
 4. The method of claim 1, wherein the set of printingparameters include a thickness of the powdered material.
 5. The methodof claim 1, wherein the set of printing parameters include a temperatureof the powder bed.
 6. The method of claim 1, wherein the set ofcharacterizations includes a particle size distribution.
 7. The methodof claim 1, wherein the set of characterizations includes a density. 8.The method of claim 1, wherein performing the set of characterizationson the plurality of powder samples comprises performing measurements onthe plurality of powder samples using a pycnometer.
 9. The method ofclaim 1, wherein performing the set of characterizations comprisesmeasuring the plurality of powder samples using any of a dilatometer,flash diffusivity instrument, gas chromatography mass spectrometer, gaspycnometer, inclinometer, particle size analyzer, particle shapeanalyzer, profilometer, scale, spectrometer, thermometer, andtintometer.
 10. The method of claim 1, wherein performing the set ofcharacterizations on the plurality of powder samples comprisesperforming a computer simulation.
 11. The method of claim 1, whereincollecting the plurality of powder samples comprises collecting theplurality of powder samples from a dispenser configured to supply thepowdered material to the powder bed.
 12. A method comprising: initiatinga print job in a powder bed fusion additive manufacturing apparatusincluding a powder bed according to a set of printing parameters; andwhile performing the print job in the powder bed fusion additivemanufacturing apparatus: collecting one or more powder samples of apowdered material supplied to the powder bed during performance of theprint job; measuring a particle size distribution of the one or morepowder samples; (a) modifying the set of printing parameters employedduring the print job according to the particle size distribution of theone or more powder samples; and continuing performing the print jobaccording to the set of printing parameters as modified in (a).
 13. Themethod of claim 12, wherein: the powder bed fusion additivemanufacturing apparatus comprises a laser configured to selectively meltthe powdered material in the powder bed; and the method furthercomprises adjusting an intensity of a beam emitted by the laseraccording to the particle size distribution of the one or more powdersamples.
 14. The method of claim 12, wherein: the powder bed fusionadditive manufacturing apparatus comprises a laser configured toselectively melt the powdered material in the powder bed; and the methodfurther comprises adjusting a dwell time of a beam emitted by the laseron the powdered material in the powder bed according to the particlesize distribution of the one or more powder samples.
 15. The method ofclaim 12, further comprising measuring the particle size distribution ofthe one or more powder samples using a pycnometer.
 16. The method ofclaim 1, wherein collecting the plurality of powder samples comprisescollecting the plurality of powder samples from a dispenser configuredto supply the powdered material to the powder bed.
 17. A methodcomprising: initiating a print job in a powder bed fusion additivemanufacturing apparatus including a powder bed according to a set ofprinting parameters; and while performing the print job in the powderbed fusion additive manufacturing apparatus: collecting one or morepowder samples of a powdered material supplied to the powder bed duringperformance of the print job; measuring a density of the one or morepowder samples; (a) modifying the set of printing parameters employedduring the print job according to the density of the one or more powdersamples; and continuing performing the print job according to the set ofprinting parameters as modified in (a).
 18. The method of claim 17,wherein: the powder bed fusion additive manufacturing apparatuscomprises a laser configured to selectively melt the powdered materialin the powder bed; and the method further comprises adjusting anintensity of a beam emitted by the laser according to the density of theone or more powder samples.
 19. The method of claim 17, wherein: thepowder bed fusion additive manufacturing apparatus comprises a laserconfigured to selectively melt the powdered material in the powder bed;and the method further comprises adjusting a dwell time of a beamemitted by the laser on the powdered material in the powder bedaccording to the density of the one or more powder samples.
 20. Themethod of claim 17, further comprising measuring the density of the oneor more powder samples using a pycnometer.